New free tripwire: eval:bg:gate / eval:bg:periodic --timeout must cover
ceil(shards/jobs) x shard-timeout x 1.05, recomputed from the actual paid
test census every run. Hand-derived numbers go stale every time a paid
file lands — the review split just proved it: periodic's 28800s dropped
BELOW its new 32130s worst case (raised to 32400s here). An undersized
watchdog kills healthy runs and the tail reports never-started.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>